According to the Study by Robert Constanza Et Al

According to the study by Robert Constanza et al., the following its true:

A) nature provides more services to humanity than the human economy does.
B) the calculation of GDP largely accounts for nature's services.
C) it is easy to calculate the direct value of nature's services, especially when those services are no longer provided.
D) the finite nature of exhaustible resources is a more pressing issue than the deterioration of the ecosystem that provides nature's renewable resources.